Rosin amine treated natural cellulose fibers



Patented May 15, 1951 ROSIN AMINE TREATED NATURAL CELLULOSE FIBERS Joseph M. Almand, Hogansville, Ga., assignor to United States Rubber Company, New York,

N. Y., a corporation of New Jersey No Drawing. Application August 2, 1948, Serial No. 42,140

15 Claims. (Cl. 8116.2)

This invention relates to improved cellulosic fibers, yarn or cord and a method of improving its tensile strength.

U. S. patent to H. M. Buckwalter No. 2,297,536 covers the treatment of native cellulosic fibers with non-volatile, non-waxy, water-soluble, cotton-Wax-peptizing agents which contain a tricyclic hydroaromatic condensed nucleus, particularly with aqueous solutions of alkali metal salts of rosin acids and their derivatives to improve the tensile strength thereof. U. S. Patent 2,422,078 to the same inventor similarly covers the treatment of native cellulosic fibers with aqueous solutions of alkali metal salts of acids of run native Congo copal resin. One of the results brought about by the treatments covered in these patents is a substantial and commercially important increase in the tensile strength of the cotton yarns, cords, etc. The treating agents mentioned may be referred to as being active and thedegree of activity which they possess may be expressed in terms of the percentage increase in tensile strength which they impart to grey cotton fiber. g

I have now found that condensed and uncondensed polynuclear hydroaromatic primary amines possess textile strength-improving activities comparable with those exhibited by the treating agents referred to above, particularly the alkali metal salts of the rosin acids. The amine may be used either as such or in form of a salt thereof. Where the amine itself is used, I prefer to apply it to the grey cotton yarn or the like in the form of an aqueous dispersion thereof or in the form of an aqueous emulsion of a solution of the amine in a suitable volatile organic solvent. The amine could also be applied in the form of a solution in a volatile organic solvent.

I prefer however to apply the amine in the form of a water-soluble salt thereof in solution in Water. v

Any polynuclear hydroaromatic primary amine may be used in the practice of my invention. An example of an uncondensed polynuclear hydroaromatic amine which can be used in the present invention is orthoaminodicyclohexyl. I prefer, however, to employ the amines which contain a condensed tricyclic hydroaromatie nucleus and particularly such amines which have the genera formula where ring A is a hydroaromatic ring, where ring B may be hydroaromatic or semi-aromatic. and where ring C may be hydroaromatic, semi aromatic or aromatic. Specific examples of such condensed polynuclear hydroaromatic amines are dehydroabietylamine, tetrahydroabietylamine; dihydroabietylamine and dextropimarylamin'e; and particularly a mixture of the latter four amines which is known commercially as Rosin Amine D which is described by J. N. Borglin.

in an article appearing in Soap and Sanitary Chemicals, December 1947. The major components of Rosin Amine D are stated by Borglin to be as follows:

CH3 CHzNHz CH: CH NHg Dehydroabietylamine I Tetrahydroabietylamine I CH3 CHzNHz CH3 CHzNHg I I i CH3 CH=CH,. o -c1-1,

CH1 CH CH Dihydroabietylamine Dextropimarylamine The components of Rosin Amine D are made from, but are not derivatives of, disproportionated rosin acids in a manner well known to thoseskilled in the art. Processes for effecting the disproportionation of rosin are well known in the art; processes based on the use of a palladium catalyst are described by Fleck et al., J. A. C. S., 60, 159 (1938), and by Littmann, U. S. Patent No. 2,154,629. The disproportionated rosin acids may then be converted to the corresponding primary amines .in any suitable manner known to the art, for example by converting them to the nitriles and then reducing the nitriles to the primary amines. Rosin amines are described in detail in a pamphlet entitled Rosin Amines issued by the Naval Stores Department of Hercules Powder Company under date of Feb ruary 1, 1948. Rosin Amine D as commercially available contains at least 88% of rosin amine and often .as much as thereof. A

3 typical analysis .and characteristic physical properties of Rosin Amine ;D are as follows:

Bromine number (KBlKBlO3) I 49 N Viscosity at 25 C... 4:670 centistokes Boiling range (5 mm'.) l87-2l1 C.

Boiling range (760 mm.)

on) Flash point (Cleveland Open Cup) 192 C. Heat of vaporization 20,100 calories per mole v Neutralization equivalent 317 Although the disprcportionated rosin acids and Rosin Amine D have identical condensed ring structures, they differ in their respective functional. groups. The functional group of the disproportionated rosin acids :is --COOH (carb'oxyl), whereas thefunctional' group of the compounds which are employed in accordance with the-present invention is -N-H2 (primary amino). The water-soluble rosin :acids salts :are anionic (R;COO-M+) whereas the water-soluble salts of the amines used in my invention are cationic (RNH3+.A") active "chemicals.

Instead of dehydroabietylamine, tetrahydroabietylamine, dihydroabietylamine and dextropimarylamine, I may use in the practice of my invention primary amines of other rosin nuclei, for example, abietylamine, dihydrodextropimarylamine, etc. I may use the practice of my invention the amines of the nuclei of the rosin acids found in ordinary rosin such as abietic acid, ,pimaric acid, sapinic acid, or in modified rosins,.i. e., rosins which have been chemically modifiedto-chemically change the rosin nucleus, e. g., heat treated rosin, isomerized rosin, polymerized rosin, hydrogenated rosin, etc. I prefer to use the mixture available commercially as Rosin Amine D identified above.

In the preferred practice of my invention wherein I treat the grey cotton fiber with an aqueous solution of the amine salt, .I may use any water-soluble salt of the foregoing amines. The acids capable of forming suificiently watersoluble salts of the polynuclear hydroaromatic primary amines appear to be limited to monobasic inorganic acids, e. g., hydrochloricacid, and monobasic organic aliphatic carboxyl-ic acids having. from 1 to 4 carbon atoms per molecule, examples being formic, acetic, propionic and butyric acids among the unsubstituted saturated monobasic aliphatic acids, and glycolic, lactic and alpha-hydroxy butyric acids among the alpha-hydroxy saturated monobasic aliphatic acids. Where organic acids are used to form the salt I generally use saturated acids. Attempts to make water soluble salts of such amines with inorganic and organic polybasic acids and with aromatic monoand poly-basic carbox-ylic acids and with sulfonic acids havenot been successful.

The hyd-roaromaticity of the amines used in the present invention is essential to the textile strength-improving activity of such amines. The textile strength-improving activities of aliphatic and aromatic amines are practicallyzero.

The :amines of the present invention may be I applied to the grey cotton fiber in the same manner as described in Buckwalter U. S. Patent No. 2,297,536, typically, by applying to "the grey cotton yarns or the like, an aqueous solution ofthe wateresoluiole s'altsuof the amines :ofthecpress ent invention followed by removal :of the excess solution in any suitable manner, as by use of a vacuum, followed by drying at a suitable elevated "temperature at which the water present will be driven off- The .same type of apparatus as shown in that patent may be used in applying the amines of the present invention. The theory of the action of the amines of the present invention is believed to be the same as that described for the compounds covered in U. S. Patent No. 2,297,536. The treatment with the amines of the present invention confers upon the treated cotton the characteristic that it shows upon hot ethyl alcohol extraction of substantially all the alcohol-soluble material a tensile strength-improvement which can be detected but which is less than 9% and generally is less than 5%. This is in contradistinction to untreated grey cotton yarn or cord which, upon extraction of substantially all the alcohol-soluble material with hot ethyl alcohol, exhibits .a gain in tensile strength of the order of 10 to 15% due to the removal of cotton waxes normally present on the fibers.

The present invention is applied to grey cotton which contains at least of the original naturally occurring cotton waxes and generally sub stantially all of the original waxes.

'Where the amine of the present invention is applied to the grey cotton yarn or the like "in the form of an aqueous solution of a water-soluble salt of the amine, the concentration thereof may vary widely. However, it is preferred to employ a concentration of at least 0.5% by weight of the amine in the treating solution, concentrations below 0.5% generally giving an insufiic'ient improvement for commercial practice. Generally speaking, above 20% concentration, the resulting solutions are too viscous for practical use. I therefore prefer to employ a concentration within the range of from 0.5 to20%. Within this range, the improvement in tensile strength appears to increase roughly proportion ally with the increase in concentration. .Th'e foregoingv percentages refer to the amine as such combined in the salt rather than to the salt, although the difference is generally slight due to the high molecular weight of most of the amines used.

The invention is of special utility in connection with the production of tire cord from which rub; berized fabric plies are made, which in turn become part of the pneumatic tire carcass. By reason of the improved tensile strength of the d unrubberized tire cord, it is possible to make a standard quality tire with less tire cord, or in the alternative to make a superior tire with the usual quantity of tire cord. Thus the chemically treated grey cotton cords may with or without intermediate drying be immersed in a rubber latex composition for the making of weftless cord fabric for tire carcasses. The latex composition, when dry, ultimately acts to bind the cords in parallel relation.

'The treated grey cotton of the present invention usually finally contains at least 0.1% by weight of the amine. The increase in weight, on the bone dry basis may range from 0.1 to 2% by weight as a result of the treatment.

The invention may be applied to treating finished tire cords made of grey cotton or to grey While rubberizing of the treated cotton'has been referred to as illustrative of further processing, it will be apparent that various uses of the grey cotton will not require rubberizing and that production of unrubberized fabrics, including the treated cotton, is also included within the broad scope of the invention.

The temperature at which the treatment with the amine is conducted may vary over wide limits but preferably is between 25 C. and 100 C. In general, the use of temperatures in the upper portion of this range gives better results than temperatures in the lower portion.

. .The' time of treatment ma similarly vary widely but preferably ranges from 2 to 60 seconds.

' The following reports experimental work which was conducted in accordance with the present In the following data grey cotton cord was treated with aqueous solutions of water-soluble salts of amines of the present invention without stretching. The tensile strength of the cotton cord was measured at 70 F. and 60% relative humidity as is standard in the art. In the tables the expression RAD designates the commercially available mixture of disproportionated rosin amines known as Rosin Amine D described in the Borglin article mentioned above and comprising as major components dehydroabietylamine, tetrahydroabietylamine, dihydroabietylamine and dextropimarylamine. The treatment, except where otherwise indicated, involved soaking the grey cotton with the aqueous solution of the amine salts for one minute at 95100 0., followed by vacuum removal of surplus solution and drying at 110 C. In all cases the grey cotton treated was in the form of cord of carded American cotton having the construction known in the art as 12/4/2, a tensile strength of 16.6 pounds when untreated, an elongation at pounds tension of 7.75%, containing 1145 yards per pound and having a gauge of 0.0317 inch. The solutions of the amine salts employed had a pH of '7-8 and contained the indicated percentage of the amine itself rather than the salt thereof.

In the first series of tests the grey cotton cord just described was treated in the manner described with 10% aqueous solutions of RAD formate, acetate, propionate, glycolate, lactate and 5 Table 2.- o.-Ami1zodicyclohe:cyl

ACETATE 10%sonur10u Tensile Lbs. Rtg.

Control 16. 100. 0 Acetate 18.58 112.0

Similar tests reported in Tables 3 and 4 were conducted on the same cotton cord which had been dewaxed by hot alcohol extraction and upon viscose rayon cord, respectively. The results show that no improvement was effected in the dewaxed cotton or rayon by the treatment of the present invention. The rayon cord used Was that known in the art as 1650 denier 2 ply.

Table 3.RAD acetate (10%) EFFECT ON DEWAXED COTTON Table 5 shows the variation in the activity of several amine salts reported upon in Table 1 as a function of concentration of amine in the aqueous treating solution. In these tests the grey cotton cord described above was used.

Table 5.-RAD salts CONCENTRATION vs. TENSILE hydrochloride and of o-aminodicyclohexyl acetate RAD" Formate Acetate Lactate g d solut1on. The tens1le strengths and ratlngs of the control and of the treated cords are given in Tables 1- and 2. Tensile Tensile Tensile Tensile r 00 Ooncn Lbs. Rtg. Lbs. Rtg. Lbs. Rtg. Lbs. Rtg. Table 1.-RAD salts C 7 0ntrol... 16.60 100.0 16.60 100.0 16.60 100.0 16.60 100.0 10% SOLUTIONS 2.5%--. 19. 41 117.0 18.87 113.7 19.05 114.8 18. 94 114.1 5.0%--. 19.70 118.7 10.52 117.5 19.82 119.5 19.20 116.2 10.0% 19.82 119.3 19.68 118.3 20.10 121.4 20.33 122.5 Tensile 20.0% 19.78 119.3 20.58 123.8 20.55 123.8 20.80 125.3

Salt

Lbs. Rtg. Grey cotton cord, such as was used in the pre- Control 16.60 100.0 vious tests, was treated with RAD acetate in the figggig manner described above and was then washed for Propionatc. 19. 16 115.3 10 seconds in tap water at 18 C. The results, re ggfg gffi; 2 59;; ported in Table 6, show that the effect of the Hydrochlor treatment with the amine salt is not removed by 3 76 washing with water; 7

autegsee Tensile Lbs. Rtg.

Control; 16. 60 100. O Acetat 19. 68- 118. 3

Acetate 19. 68 100. Acetate and Wash 19. 60 99. 7

The-:resultswhich:arezreported-in Tables 7 and: 8' show that-the 1 treatment of the present-i invention may be satisfactorily conducted over atemperature range of from= 25" Cl to 100C-1 and overa period of time ranging from 2 to 60 seconds;

Table 7 .RAD acetate EFFECT OF TREATIN G TEMP.

Tensile Temp., O.

Lbs. Rtg.

Controll i Treat Treat 7 Table 8.-RAD- acetate (-10 EFFECT OF TREATING TIME Tensile Time, Sec.

Lbs. Rtg.

Grey cotton cord of the above type Was treated withiRAD acetate as describedzin connection with Table I and w a's then, withoutdrying; treated at-atemperature' of="2'5 C. with a-GR S latex: con taining 30% solids; 'Ihe-results-reported'in Pa--- ble 9 show that the latex treatmentdoes not' Tmpair the improvement in tensile strength brought about by the presentrinventiom TabZe.9.RAD acetate (1 0 EFFECT OF LATEX Tensile Lbs. Rtg.

Control 16.60 100. 0. Acetate 1968 11833' Acetate '19. 68- 100. 01 A'cetate andLatex .l 19.64 99.9"

on theirfbreakingr point: After: the (10rd orf'yarn isestretched tcr'the'prop'enextend; itfi'stdrie'diwhile' its stretched length maintained: thatfis, with out permitting? shrinkage; andfa's referred to -in British Patent No'; 545,7'l'einvolving drying whil'et maintaining the: cord? or yarn under a": uniform state of length.

TREATMENT WITH STRETCHING.

The? following experimental work? illustrates: the practic'einf my invention wherein grey cotton; yarn-s which had: been treated: With a solution: 01? the amine was stretched. or 'tensionedito: a point? just short-ofitsbreakingpoint while.- stilliwet with the treating'solution andiwaszthem dried un der the resulting tension.

The' grey cotton-yarn, used'was thattlinownin the art: as1-6.61076--Karnak: In thefirstseries? of tensionin tests the yarn was soaked for. approxi' mately one minute with a 1.75% aqueous solution of Rosin Amine D acetate (containing 1.75% by Weight of the amine), was tensionedv while wet to a point'just short of "its breaking point and. was then dried under the resulting tension at IIO 'CI The tensilest'rength of the resultin'g'yarn was 39.43' pounds in comparison to a tensile" strength of'25.99 pounds for the untreated, yam or an improvement of 51.7%. p

In another series of experiments thesame grey cotton yarn was treated inexactly" same mannerwith an aqueous solutionconsistingof by volume of'a 1.75% by weight solution ofsodi um abietate and 30% by volume of a 1.75f%- By weight solution of 'Rosin Amine D acetate. The" resulting yarn had a tensile strength1of'40'12Z1 pounds comparedt'o 25.11 pounds for theuntreated yarn or an improvement of 602%. With a: 1.75% solution of sodium abietate alonetthe treated yarn hada tensile strengthv of 39162" pounds or an improvement'of 57 .8'% over the'cone troll This illustrates that. an unexpected increase in tensile strength, is made possible using theamines of the present invention in com;- bination with alkali metal salts of rosin acids, since. theincrease obtained with the combination is greater than theiincrease obtainedwith either'the. amine alone or the"alkalLmetalIsaltL of. the rosin acid alone. 'Iherelatii/e proportions of the amine and the alkali salt of the rosi-nacidi may vary widely, say from. 20%. up. to.-100.%.. of the.amineand.correspondingly from..80,%. to 0% of the -alkali metal salt of. thevrosin acid;

In still anotherseries of experiments-the same, grey cotton yarnwas first treated Wlllhr a. 10% aqueousv solution. of. trisodiumt phosphate,v dried. thensoaked-as before inthe same 1.75 %-.solution: of Rosin Amine D acetate, tensioned-asrbefore while wet therewith and then dried under the resulting tension. The tensile strength of the resulting yarn was:.40.86?=pounds'in= comparison to a tensile strength of 25.11 pounds for the control. This shows that precipitation of the rosin amine as the insoluble rosin amine phosphate givesre sults. equivalent to those obtained where the amine is present in the treated cotton in the form of a; Water-soluble salt thereof.

A very importantadvantage of the treatment of. the present invention isthat it adds greatly to; the mildew-resistance of the yarn or cord. Thus,..

. the same grey cotton yarn that was used in the:

preceding tests was exposed to. mildewing fungi.v for a period of four weeks at room temperature and relative humidity: Samples of" both" untreated yarn and yarn which had been treated with the 1.75% solution of Rosin Amine D acetate, followed by tensioning and drying as in the preceding tests, were exposed to these mildewing conditions. At the end of the tests, the treated yarn had a tensile strength of 34.09 pounds in comparison to a strength of 39.43 pounds at the beginning of the tests, whereas the untreated yarn had a tensile strength of 15.30 pounds after exposure in comparison to a strength of 26.79 pounds at the beginning of exposure. Thus, the treated yarn had considerably more strength aft-r er exposure than the untreated yarn had before exposure. The percentage reduction in strength as a result of the mildewing exposure was 42.8% for the untreated yarn as against only 13.6% for the treated yarn.

While the foregoing. description is chiefly concerned with improving the tensile strength of grey cotton fibers, it may be extended to naturally occurring cellulosic fibers in general which have substantially their native composition, for example, flax, hemp, jute, etc.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. Grey cotton containing at least 75% of the original naturally occurring waxes and having an improved tensile strength as a result of impregnation with dehydroabietylamine in an'inert liquid medium.

2. Grey cotton containing at least 75% of the original naturally occurring waxes and having an improved tensile strength as a result of impregnation with dihyclroabietylamine in aninert liquid medium.

3. Grey cotton containing at least 75% of the original naturally occurring waxes and having an improved tensile strength as a result of impregnation with tetrahydroabietylamine in an inert liquid medium.

i. Grey cotton containing at least 75% of the original naturally occurring Waxes and having an improved tensile strength'as a result of impregnation with .a mixture comprising dehydroabietylamine, dihydroabietylamine, tetrahydro abietylamine and dextropimarylamine in an inert liquid medium.- v

5. Grey cotton containing at least 75% of the original naturally occurring waxes and. having an improved tensile strength as a result of impregnation with an aqueous solution of amixture of water-soluble salts of dehydroabietylamine, die hydroabietylamine, tetrahydroabietylamine and dextropimarylamine.

6. Naturally occurring cellulosic fibers containing-at least 75% of the original naturally occurring Waxes and having an improved tensile strength as a result of impregnation with a mixture of primary rosin amines comprising dehydroabietylamine, dihydroabietylamine, tetrahydroabietylamine and dextropimarylamine and sodium abietate in an inert liquid medium.

7. Naturally occurring cellulosic fibers containing at least 75% of the original naturally occurring waxes and having an improved tensile strength as a result of impregnation with an aqueous solution comprising water-soluble salts of dehydroabietylamine, dihydroabietylamine, tetrahydroabietylamine and dextropimarylamine and sodium abietate.

8. A process of improving the tensile strength of naturally occurring cellulosic fibers containing at least 75% of the original naturally occurring waxes Which comprises impregnating said fibers with a compound selected from the group 10 consisting of primary rosin amines having the general formula :1 '5

where ring A is hydroaromatic, ring B is a ring selected from the group consisting of hydroaromatic and semi-aromatic rings; ring Cis a ring selected from the group consisting of hydroaromatic, semi-aromatic and aromatic rings, and R is selected from the group consisting of where ring A is hydroaromatic, ring B is a ring selected from the group consisting of hydroaromatic and semi-aromatic rings, ring C is a ring selected from the group consisting of hydroaromatic, semi-aromatic and aromatic rings, and R is selected from the group consisting of CH3 CH3 and water-soluble salts of said amines, said compound being applied in an inert liquid medium.

10. A process of improvingthe tensile strength of grey cotton containing at least of the original naturally occurring waxes and which comprises impregnating said grey cotton with an aqueous solution of a waterasoluble salt of a primary rosin amine having the general formula where ring A is hydroaromatic, ring B is a ring selected from the group consisting of hydroaromatic and semi-aromatic rings, ring C is a ring selected from the group consisting of hydrolei aromaticssemitaromatic ndaromatic rin sgand Ris selected from the group consistingxif CH3 GHFCHI C CH3 and , H3 11. A process as in claim wherein the concentration of said aminein said solution is from 0.5% to said percentages being by weight.

12. A processasin claim 10 wherein the concentration of said aminein said solution is from 0.5% to 20%, said percentages being by weight, and sai impre nat ng is car i d on a a i-temp ra ure :o 1mm C- to 0 .C- an :i a ti e of to fi0z eqo s iNatu 1y occurr ng pe i fi e s on- .g :at st 71 o the or inal n t a l occurring was andharin a improv d e le strength as a result of impregnation with a compound selected :from the group consisting of primary rosin amines :having the general formula where rin A is hydroaromatic, ring B is a ring selected from the group consisting of hydroaromatic and semi-aromatic rings, ring C is a ring selected from the :group consisting of hydroaromatic, semi-aromaticandaromatic rings, and R is selected from the group consisting of CH; CH,

and water-solublesal-ts of said -amines,rsaid compounds being applied in an inert liquid medium.

l fi. Grey cotton containing at least 75% of the original naturally occurring waxes and haying an :improved tensile strength -as-a result of impregnation with -a compound selected from "the group consistin of primary rosin amines having the general formula Etc d2 .Wlifile311111941315ihYfillQfiEOIIlfitiQmfiQgB is a :rin elec ed;-1:Qm the 'E'IQUD @Qn istin .of 1, aromatic and s i-aromatic :rir gs, 5a rin sel. tedirom; fig n-piconsistin o sad-roaromat ais m ra omat c and anomat irm szaiid .13 s selected cf pm the g oup Qnsistine-p 0H3 orman,

and

w er r ng .A i h d rom t a ng B is a ring selected from the group consisting of hydroaromatic and 'SQm 1 7O I Z U CIiIQES, ring ci a i ssleqted .m th group iqo sisting of hydr ar mafi s m -aroma i and ar matic rin s, and Rv i selec ed fr m t e g tq p c s t ng f and 7 CH3 Ha -05 Q Ha QB:

JOSEPH REFERENCES CITED The following references :are of record in ithe file of this patent:

UN TED STAEES PATENTS Numbe Name Date 2,186,101 Dreyfus J an. 9, 51940 2120142 iMaf 2W1, 7 i fi Sept-29,199 ,2, .3:19 issiilps er t ala. uly 1 51' 

8. A PROCESS OF IMPROVING THE TENSILE STRENGTH OF NATURALLY OCCURING CELLULOSIC FIBERS CONTAINING AT LEAST 75% OF THE ORIGINALLY NATURALLY OCCURRING WAXES WHICH COMPRISES IMPREGNATING SAID FIBERS WITH A COMPOUND SELECTED FROM THE GROUP CONSISTING OF PRIMARY ROSIN AMINES HAVING THE GENERAL FORMULA 